Fixes WebVR presentation from within VRShell.

chrome/browser/android/vr_shell/vr_shell_delegate.cc

Index: chrome/browser/android/vr_shell/vr_shell_delegate.cc
diff --git a/chrome/browser/android/vr_shell/vr_shell_delegate.cc b/chrome/browser/android/vr_shell/vr_shell_delegate.cc
index 81dcd4f2e4cafdc1d65f9ae988eafa4372dc1ec9..57872f7155514e23972b78f3be1e56402880acd0 100644
--- a/chrome/browser/android/vr_shell/vr_shell_delegate.cc
+++ b/chrome/browser/android/vr_shell/vr_shell_delegate.cc
@@ -62,6 +62,13 @@ void VrShellDelegate::SetPresentingDelegate(
   }
 
   presenting_delegate_->UpdateVSyncInterval(timebase_nanos_, interval_seconds_);
+
+  if (pending_successful_present_request_) {
+    presenting_delegate_->SetSubmitClient(std::move(submit_client_));
+    present_callback_.Run(true);

[mthiesse, 2017/03/30 15:29:46]

nit: base::ResetAndReturn(presenting_delegate_).Run(true)

Also below.

[tiborg, 2017/03/30 22:19:57]

Done.

+    present_callback_.Reset();
+    pending_successful_present_request_ = false;
+  }
 }
 
 void VrShellDelegate::RemoveDelegate() {
@@ -75,10 +82,22 @@ void VrShellDelegate::RemoveDelegate() {
 
 void VrShellDelegate::SetPresentResult(JNIEnv* env,
                                        const JavaParamRef<jobject>& obj,
-                                       jboolean result) {
+                                       jboolean success) {
   CHECK(!present_callback_.is_null());
-  present_callback_.Run(result);
+  if (success && !presenting_delegate_) {
+    // We have to wait until the GL thread is ready since we have to pass it
+    // the VRSubmitFrameClient.
+    pending_successful_present_request_ = true;
+    return;
+  }
+
+  if (success) {
+    presenting_delegate_->SetSubmitClient(std::move(submit_client_));
+  }
+
+  present_callback_.Run(success);
   present_callback_.Reset();
+  pending_successful_present_request_ = false;
 }
 
 void VrShellDelegate::DisplayActivate(JNIEnv* env,
@@ -121,10 +140,6 @@ void VrShellDelegate::Destroy(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   delete this;
 }
 
-device::mojom::VRSubmitFrameClientPtr VrShellDelegate::TakeSubmitFrameClient() {
-  return std::move(submit_client_);
-}
-
 void VrShellDelegate::SetDeviceProvider(
     device::GvrDeviceProvider* device_provider) {
   if (device_provider_ == device_provider)